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Benchmark AHB2 amplifier measurement by JonMarsh

Olli

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That is one of the most interesting upcoming tests for me - if the AHB2 beats Hypex on the bench.
 

filo97s

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That is one of the most interesting upcoming tests for me - if the AHB2 beats Hypex on the bench.
judging from the THD+N graph posted, it seems that the Benchmark beats the Hypex with a +2dB in sinad. Quite possibly is the first and only amp that can outperform an NC400 module, indeed it's based on a THX AAA topology; if you want to know more about the tech inside that monster: https://benchmarkmedia.com/blogs/ap...ory-use-of-the-benchmark-ahb2-power-amplifier
Key points are, quoting from that page:
  • Linear class-AB amplifier with parallel class-A feed-forward amplifier
  • Patented THX AAA low-distortion topology.
  • Class-H tracking rails extend output power and voltage while maintaining high efficiency
  • Switching power supply operating well above the audio band (above 500 kHz). The high frequency operation eliminates large line-frequency transformers that emit large magnetic fields. The high frequency design allows internal filtering that does not interfere with the audio bandwidth. The exceptionally low magnetic emissions allow a compact package without compromising the noise performance.
The AHB 2 is using an SMPS, in contrast with all those audiofoolish unfounded statements that see linear power supply as the best supply ever.
 

Olli

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Yes, read that — and bought 2 and a DAC3B with them. They are just great in my set-up, but I am also very impressed with March Audio‘s P252 which is Hypex based. So I am dying to see Amir‘s unbiased final evaluation :)
 

Sawdust123

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When the APx-555 was first shown at AES, we spent a good portion of setup day testing the AHB2. None of us had ever seen an amp that powerful with distortion numbers that low. We were very close to the resolution limit of the analyzer. It would be interesting to test it with the new B series 555 as its generator is a little cleaner.
 

Willem

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Question: will the improvement be audible compared to other good power amplifiers? You could argue that this does not matter that much gieven the quite decent price for a product this good - this is not audiophile pricing. On the other hand, if I can get a sonically identical product for half or even a quarter of the price, why not?
 

Shadrach

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Question: will the improvement be audible compared to other good power amplifiers? You could argue that this does not matter that much gieven the quite decent price for a product this good - this is not audiophile pricing. On the other hand, if I can get a sonically identical product for half or even a quarter of the price, why not?
I would normally agree. But, Benchmark has years of experience in producing solidly performing products used extensively in the professional audio industry. I am told by people who use their products that they are very reliable and Benchmark have an excellent customer service.
This imo is worth paying for. Getting something that performs well but packs up is extremely frustrating.
 

Kal Rubinson

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Question: will the improvement be audible compared to other good power amplifiers? You could argue that this does not matter that much gieven the quite decent price for a product this good - this is not audiophile pricing. On the other hand, if I can get a sonically identical product for half or even a quarter of the price, why not?
I have not used any amp (at any price) in my system that sounds like the AHB2. I bought 3 of them (so far).
 

RayDunzl

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I have not used any amp (at any price) in my system that sounds like the AHB2. I bought 3 of them (so far).


Please let loose with a little subjectivity here, if you would...
 

Soniclife

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That's where I discovered that my new hero amp wasn't quite perfect. Oh, its power and resolution were still not to be faulted, but through a pair of Monitor Audio Silver 8 speakers, the sound was somewhat hard and thin.
Is this an impression that continued, or has it evolved?
 

Shadrach

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I agree on that - and the price for that is not excessive. But still, can you hear the difference?
Probably not given something else that measures as well in the audible range and the loudspeakers don't chuck up any strange impedances.
You might be very hard pressed to find that sort of power at the price.
 

Kal Rubinson

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Is this an impression that continued, or has it evolved?
I cannot say because I bought the amps for use in my NYC system and I don't use it with the Monitor Audio Silver8s in my CT system.
 

restorer-john

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When the APx-555 was first shown at AES, we spent a good portion of setup day testing the AHB2.

What is your take on the IMD (19/20KHz) performance? The HF IMD tests are hardly SOTA are they? A FFWD system that is optimised for LF-Mid, not HF?

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That said, it's a lovely thing to look at, although it's not going to be a repairable product apart from at the factory, perhaps (if you are lucky) an output stage rebuild or entire board replacements...

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Gotta love a stereo power amplifier that needs a Spartan-6 FPGA... :)
 

March Audio

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Yes, read that — and bought 2 and a DAC3B with them. They are just great in my set-up, but I am also very impressed with March Audio‘s P252 which is Hypex based. So I am dying to see Amir‘s unbiased final evaluation :)
@Olli Very interested to get your feedback on what differences do you hear between the P252 and the AHB.

Well ignore the 3x price differential ;)
 
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restorer-john

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Just curious John :) what is your expectation for state of the art?

Better IMD numbers that's all.

I reckon I could find a dozen test reviews of amplifiers with better published numbers for IMD.
 

Dana reed

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Have you heard of anyone using these in mono with a 4 Ohm load like Magnepans? Would be interesting to see how many Watts these can put out to a load like that before clipping and/or thermal issues.
 
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